scholarly journals Recent Advances in the Deposition of Diamond Coatings on Co-Cemented Tungsten Carbides

2012 ◽  
Vol 2012 ◽  
pp. 1-14 ◽  
Author(s):  
R. Polini ◽  
M. Barletta ◽  
G. Rubino ◽  
S. Vesco
Keyword(s):  
Chemical Vapour ◽  
Deposition Process ◽  
Tungsten Carbides ◽  
Diamond Coatings ◽  
Carbon Dissolution ◽  
Thermal Expansion Coefficients ◽  
Hard Metals ◽  
To Receive ◽  
And Diffusion

Co-cemented tungsten carbides, namely, hard metals are largely used to manufacture high wear resistant components in several manufacturing segments. Coating hard metals with superhard materials like diamond is of utmost interest as it can further extend their useful lifespan. The deposition of diamond coatings onto WC-Co can be extremely complicated as a result of poor adhesion. This can be essentially ascribed to (i) the mismatch in thermal expansion coefficients between diamond and WC-Co, at the typical high temperatures inside the chemical vapour deposition (CVD) chamber, generates large residual stresses at the interface; (ii) the role of surface Co inside the WC-Co matrix during diamond CVD, which promotes carbon dissolution and diffusion. The present investigation reviews the techniques by which Co-cemented tungsten carbides can be treated to make them prone to receive diamond coatings by CVD. Further, it proposes interesting ecofriendly and sustainable alternatives to further improve the diamond deposition process as well as the overall performance of the coated hard metals.

Diamond Coatings on Surface-Modified Carbide Tools Using KrF Pulsed Laser

1997 ◽  
Vol 505 ◽  
Author(s):  
Dong-Gu Lee ◽  
Rajiv K. Singh
Keyword(s):  
Heat Treatment ◽  
Surface Morphology ◽  
Laser Energy ◽  
Diamond Films ◽  
Pulsed Laser ◽  
Chemical Vapor ◽  
Deposition Process ◽  
Cemented Carbide ◽  
Tungsten Carbides ◽  
Diamond Coatings

ABSTRACTThe surface of a cemented carbide was modified using a KrF pulsed laser process to achieve a microrough structure, leading to stronger adherence of diamond films to cemented carbide substrates. The surface morphology and roughness were investigated with laser conditions. After the surface modification with the laser and the etching of the modified surface, heat treatment was performed prior to deposition of diamond film in order to observe changes in surface morphology and adhesion. Diamond films were grown by chemical vapor deposition process. The results indicated that the heat treatment of the modified cemented carbide improved the adhesion of diamond films by the recrystallization of tungsten carbides into the fine and long grains. As laser energy for the modification of a cemented carbide increased, the surface roughness increased and tungsten carbide (WC) was transformed to WC1−x(X =0–0.3) and then to W2C.

CVD Diamond Coatings for Machining

2006 ◽  
Vol 526 ◽  
pp. 55-60 ◽  
Author(s):  
D. Moulin ◽  
O. Raymond ◽  
P. Chevrier ◽  
Paul Lipiński ◽  
Thierry Barre
Keyword(s):  
High Performance ◽  
Metal Cutting ◽  
Thermal Stresses ◽  
Chemical Vapour ◽  
Surface Preparation ◽  
Deposition Process ◽  
Cvd Diamond ◽  
Tool Geometry ◽  
Diamond Coatings ◽  
Machined Surface

Machining of modern materials requires high performance tools. More than 60% of metal cutting tools used are coated to limit abrasive wear. As the harder material known to man, diamond and consequently Chemical Vapour Deposited (CVD) diamond coatings allow to increase performances of tungsten carbide tools, i.e. tool life, machined surface quality, and to decrease costs. However, CVD diamond coated tools quality is very dependent on the surface preparation as much as the fabrication process parameters. This paper aims to discuss the influence of pretreatments before deposition, and thermal stresses induced by the cooling operation. Diamond deposition process is described emphasizing the role of every step and its function. Some numerical simulations of the residual stresses at the interface are presented, enlightening that tool geometry is an important factor while using a coating, and that tools must be designed for the diamond coating.

Assessing the size of agricultural holdings

2020 ◽  
pp. 105-116
Author(s):  
N. I. Shagaida
Keyword(s):  
Russian Federation ◽  
Vertical Integration ◽  
Total Revenue ◽  
Large Share ◽  
State Support ◽  
The Russian Federation ◽  
Agricultural Organizations ◽  
Business Entities ◽  
To Receive

The article clarifies the concept of “agricultural holding”, using an approach to assessing the size on the basis of the total revenue of all agricultural organizations within the agricultural holding. It has been revealed that only 100 of the total number of agricultural holdings that were identified can be attributed to large business entities. They comprise about 3% of agricultural organizations in the country, while their share in the proceeds is about 37%. A large share of agricultural holdings — large business subjects under the control of Russian entities operate in one, and under the control of foreign legal entities — in three or more regions of the Russian Federation. Vertical integration within the framework of large agricultural holdings with different schemes for including the stages of processing and sale of products produced in their agricultural organizations allows them to receive advantages. Strengthening the role of large business entities in agriculture puts on the agenda the issue of differentiating approaches to taxation and state support in agriculture, depending on the size of the companies’ agricultural businesses.

Provision of Remedies for Violation of Economic, Social and Cultural Rights: A Comparative Study of the United Nations, Inter-American and African Human Rights Systems

2020 ◽  
Vol 28 (2) ◽  
pp. 298-318
Author(s):  
Roman Girma Teshome
Keyword(s):  
Human Rights ◽  
United Nations ◽  
Comparative Study ◽  
Economic Rights ◽  
Regional Monitoring ◽  
Cultural Rights ◽  
The Past ◽  
The United Nations ◽  
To Receive

The effectiveness of human rights adjudicative procedures partly, if not most importantly, hinges upon the adequacy of the remedies they grant and the implementation of those remedies. This assertion also holds water with regard to the international and regional monitoring bodies established to receive individual complaints related to economic, social and cultural rights (hereinafter ‘ESC rights’ or ‘socio-economic rights’). Remedies can serve two major functions: they are meant, first, to rectify the pecuniary and non-pecuniary damage sustained by the particular victim, and second, to resolve systematic problems existing in the state machinery in order to ensure the non-repetition of the act. Hence, the role of remedies is not confined to correcting the past but also shaping the future by providing reforming measures a state has to undertake. The adequacy of remedies awarded by international and regional human rights bodies is also assessed based on these two benchmarks. The present article examines these issues in relation to individual complaint procedures that deal with the violation of ESC rights, with particular reference to the case laws of the three jurisdictions selected for this work, i.e. the United Nations, Inter-American and African Human Rights Systems.

Effect of cluster-gradient architecture of nanostructured topocomposites on features of tribointeraction with heterophased material

2020 ◽  
pp. 130-135
Author(s):  
D.N. Korotaev ◽  
K.N. Poleshchenko ◽  
E.N. Eremin ◽  
E.E. Tarasov
Keyword(s):  
Wear Resistance ◽  
Titanium Alloy ◽  
Energy Dissipation ◽  
Phase Structure ◽  
Diffusion Processes ◽  
Structural Phase ◽  
High Wear Resistance ◽  
Wear Characteristics ◽  
And Diffusion

The wear resistance and wear characteristics of cluster-gradient architecture (CGA) nanostructured topocomposites are studied. The specifics of tribocontact interaction under microcutting conditions is considered. The reasons for retention of high wear resistance of this class of nanostructured topocomposites are studied. The mechanisms of energy dissipation from the tribocontact zone, due to the nanogeometry and the structural-phase structure of CGA topocomposites are analyzed. The role of triboactivated deformation and diffusion processes in providing increased wear resistance of carbide-based topocomposites is shown. They are tested under the conditions of blade processing of heat-resistant titanium alloy.

Shifting Roles in Continuous Advising Sessions

Relay Journal ◽  
2019 ◽  
pp. 69-72
Author(s):  
Huw Davies ◽  
Robert Stevenson ◽  
Isra Wongsarnpigoon
Keyword(s):  
Learning Process ◽  
Transformational Learning ◽  
Learning Trajectory ◽  
Learner Readiness ◽  
Linguistic Support ◽  
Reflective Dialogue ◽  
Open Mind ◽  
To Receive

It is common for learning advisors to receive a request such as conversation practice or simple linguistic support in our institution simply because learners find them accessible and friendly. Although this may not be the usual role of a learning advisor, it can be the beginning of a long-lasting reflective dialogue. Learning advisors are aware that the learners’ initial interest is not necessarily an opportunity for reflection on their learning process. Nevertheless, they also acknowledge the fact that learner readiness for reflection varies depending on the learner. Thus, while advisors appear to be “conversation partners” at first, they endeavor to create reflective dialogues by incorporating advising strategies in each session. As the learning trajectory that the learner follows is not always straightforward, keeping an open mind and engaging in each advising session is crucial. The following stories depict the importance of openness to learners’ needs and maintaining continuous advising sessions in order to generate transformational learning.

scholarly journals “Crazy Jack” and the “Gay CEO”: Visions, Entrepreneurship, and the Chinese State in the New Digital Economy

2021 ◽  
Vol 50 (1) ◽  
pp. 63-85
Author(s):  
Marina Svensson
Keyword(s):  
Social Relations ◽  
Personal Narratives ◽  
Digital Economy ◽  
The State ◽  
Business Leader ◽  
Online Spaces ◽  
Chinese State ◽  
To Receive

This article analyses the visions, careers, and companies of Jack Ma of Alibaba and Geng Le of Blue City. Jack Ma is a well-known business leader and visionary, whereas the less well-known Geng Le only began to receive more attention since launching a successful gay dating app in 2012. The article focuses on the personal narratives and visions of these two IT entrepreneurs. It provides new perspectives on the role of individual entrepreneurs in relation to the Chinese state’s global ambitions and vision of creating a “strong internet country.” It argues that the commercialisation and platformisation of the Chinese internet, and the growing transnational nature of Chinese IT companies, serve to make them more, not less, co-dependent of the state and its visions. The internet’s emancipatory potential is today increasingly conflated with consumption, and online spaces and social relations are subject to both commodification and datafication.

scholarly journals Biomonitoring of Heavy Metals: The Unexplored Role of Marine Sessile Taxa

2021 ◽  
Vol 11 (2) ◽  
pp. 580
Author(s):  
Camilla Roveta ◽  
Anna Annibaldi ◽  
Afghan Afghan ◽  
Barbara Calcinai ◽  
Cristina Gioia Di Camillo ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Current Knowledge ◽  
Marine Species ◽  
Shallow Waters ◽  
Anthropogenic Inputs ◽  
Current Review ◽  
European Water ◽  
To Receive ◽  
Sessile Organisms

Coastal areas are known to receive significant anthropogenic inputs, mainly deriving from metropolitan areas, industries, and activities related to tourism. Among these inputs, some trace elements are listed as priority pollutants in the European Water Framework Directive, due to their ability to bioaccumulate in organisms. Many studies have been conducted on heavy metals (HMs) accumulation and on their possible effects on different edible marine species. While the most studied sessile organisms are bivalves, in the current review, we focus our attention on other sessile taxa (sponges, cnidarians, bryozoans, polychaetes, cirripeds, and tunicates), proposed as bioindicators in coastal shallow waters. Although their potential as bioindicator tools has been repeatedly highlighted in the literature, these organisms are still poorly investigated and considered for monitoring. In this context, we analyze the available literature about this topic, in order to summarize the current knowledge and identify possible applications of these organisms in a bioremediation scenario.

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